1. Field of the Invention
This invention relates generally to access doors in electronic components, and more particularly to covers for openings in computer housings through which removable media type devices are accessed. Even more particularly, the present invention relates to a cover for an access opening to an optical disk drive unit in a computer.
2. Description of the Background Art
Electronic components (e.g., computers, audio compact disk players, etc.) now typically include covers for access openings in the components. For example, computer housings typically include doors to cover openings through which trays of optical disk drives slide in and out.
For both functional and aesthetic reasons, such doors should fit into the associated openings as closely as possible. A close fit between the opening and the cover reduces the amount of dust and dirt that can enter the drive component when the cover is closed, and also provides a more pleasing appearance. Additionally, minimizing the amount that a cover protrudes from the front of a housing minimizes the risk of accidental damage (e.g., snagging the cover on clothing) to the cover.
FIGS. 1(A–D) illustrate a few of the problems encountered in trying to minimize the clearance gap between a cover and an associated opening in a housing. FIG. 1A is a cross-sectional view of a typical prior art rectangular door 102 disposed in an opening 104 of a housing 106. Door 102 is mounted on a hinge pin 108 that traverses opening 104 near the bottom of opening 104. A gap 110 between door 102 and housing 106 provides clearance for door 102 to swing between open and closed positions.
As shown in FIG. 1B, clearance gap 110 must be large enough to allow door 102 to pivot about hinge pin 108. As long as door 102 pivots about an axis passing through opening 104, opening 104 must be at least as wide as the diagonal dimension (D) of door 102. Thus, the limiting minimum value of gap 110 is equal to one-half of the difference between the diagonal of door 102 and the width of door 102, assuming the top and bottom gaps are equal. Further, the distance from the center of hinge pin 108 to the edge of opening 104 must be slightly larger than the distance from the center of hinge pin 108 to the bottom front corner of door 102, otherwise the corner of door 102 will jam.
FIG. 1C shows an example of an over-size cover 112 that completely covers opening 104. Although cover 112 completely hides opening 104, it is unnecessarily large, and requires a hinge pin 114 mounted forward of the front plane of housing 106. Further, at least a portion 116 of cover 112 must be disposed forward of the front plane of housing 106, thus increasing the chance of accidental damage to cover 112.
FIG. 1D is a cross-sectional view of yet another door mechanism including a beveled cover 118 disposed in a beveled opening 120 in a housing 122. This design also requires that the hinge 124 be mounted forward of the front plane of housing 122. Otherwise, if door 118 is hinged at a location 126 within opening 120, beveled edge 128 of door 118 will jam against the beveled edge of opening 120. Further, it is difficult to mount and/or conceal a hinge at the thin beveled edge of cover 118.
Providing a close fit between a cover and an opening also creates significant alignment problems. For example, if a rectangular cover becomes slightly misaligned, it may jam in the opening, or fail to close. Similarly, if a beveled cover becomes misaligned, it will not seat properly in the beveled opening.
In addition to minimizing the gap between a cover and an opening, and minimizing the forward protrusion of the cover, it is also desirable for covers to operate with any device that may travel through the opening. Known covers typically include rearwardly projecting structures that serve retaining and/or retraction functions. Such structures operate through the opening, and may, therefore, interfere with the operation of some devices.
What is needed is a cover for an opening in a housing with a minimal clearance gap between the cover and the opening. What is also needed is a cover that minimizes any forward protrusion of the cover with respect to the front plane of the housing. What is also need is a cover whose hinge and/or retraction mechanism is hidden from view when the cover is in the closed position. What is also needed is a cover that is easy to align and maintain alignment with the opening in the housing.